JP4901743B2 - COMMUNICATION TERMINAL DEVICE, COMMUNICATION CONTROL DEVICE, RADIO COMMUNICATION SYSTEM, AND COMMUNICATION METHOD - Google Patents

Description

  The present invention relates to a wireless communication system that performs communication by selecting a transmission format according to reception quality in a multicarrier communication system.

  Conventionally, in a mobile communication system, communication is performed by a multiple access method in which a plurality of mobile stations are simultaneously connected to one base station in a cell to perform wireless communication. In recent years, there has been a demand for higher speed and higher capacity of data communication in such a multiple access method, and research in this field has been actively conducted.

  As one method for realizing high capacity, efficient packet scheduling at the base station is considered. As one of them, a method for efficiently scheduling packets based on information on propagation path conditions from each mobile station has been proposed. In a high speed downlink downlink packet access (HSDPA) in a W-CDMA (Wideband Code Division Multiple Access) mobile communication system, a mobile station uses a CQI (Channel Indication) as a channel status information of downlink radio communication. A method has been proposed in which the base station reports to the base station and the base station performs packet scheduling based on the CQI reported from each mobile station.

  Currently, 3GPP (3rd Generation Partnership Project) is a one-cell repetitive OFDM that adopts OFDM (Orthogonal Frequency Division Multiplex) communication system, which is one of the multi-carrier communication systems, as a downlink wireless communication system in preparation for standardization of the next generation communication system. (TDMA, FDMA) (Orthogonal Frequency Division Multiplex / Time Division Multiple Access, Frequency Division Multiple Access) Communication systems are being studied. In this communication method, in a multi-cell environment composed of a plurality of cells, communication is performed using the same frequency in all cells, the modulation method used for communication is OFDM, and the access method is TDMA or FDMA. It is a technology that.

  Hereinafter, OFDM, TDMA, and FDMA, which are elemental technologies of the OFDM / (TDMA, FDMA) communication system, will be briefly described.

  First, the OFDM communication system is also used in a 5 GHz wireless LAN (Local Area Network) system, in which tens to thousands of carriers are arranged at the minimum frequency interval where no theoretical interference occurs, and at the same time This is a communication method. In a normal OFDM communication system, this carrier is called a subcarrier, and communication is performed by modulating each subcarrier with a modulation system such as QPSK (Quadrature Phase Shift Keying), 16QAM (Quadrature Amplitude Modulation), 64QAM, or the like.

  Next, the TDMA communication method is a method in which each mobile station performs wireless communication by dividing time when transmitting and receiving data. Usually, in a communication system using TDMA as an access method, a frame configuration having a plurality of slots, which are units of time for communication, is used.

  Next, the FDMA communication system is a system for dividing and accessing the frequency when transmitting and receiving data. Usually, in a communication system using FDMA as an access method, a frequency is divided into several bands, and a mobile station performing wireless communication is distinguished by dividing a frequency band to be accessed.

  Next, OFDM / (TDMA, FDMA) will be described based on the above introduction. FIG. 10 is a diagram illustrating an example of an OFDM / (TDMA, FDMA) two-dimensional frame configuration. In FIG. 10, the vertical axis represents frequency and the horizontal axis represents time. One of the rectangles is a minimum unit used for data transmission. In this specification, the rectangle is referred to as a slot, and a plurality of slots arranged periodically is referred to as a frame. A slot is composed of a plurality of OFDM symbols.

  FIG. 10 shows a configuration example of the downlink communication frame, and the frame is composed of 9 slots in the time axis direction and 12 slots in the frequency axis direction. When performing wireless data communication from a base station to a mobile station, the base station can transmit data by assigning each slot constituting a frame to a separate mobile station, or assign all slots to one mobile station. It is also possible to perform wireless communication by assigning.

Non-Patent Document 1 discloses an OFDM communication method proposed by 3GGP. In Non-Patent Document 1, as a downlink transmission format, communication that improves the communication efficiency of the entire cell by efficiently using a slot obtained by dividing one communication section in the frequency direction and the time direction in a plurality of mobile stations. A method is being considered. In the downlink radio communication scheme, a plurality of modulation schemes, coding rates, and spreading factors are combined, and each slot is assigned to a mobile station having a good channel condition in accordance with the channel condition of each mobile station. To improve the throughput of the entire cell and obtain a multi-user diversity effect, and when the propagation path conditions deteriorate or when the mobile station moves fast, use the entire frequency bandwidth or a part of it, and more There has been proposed a communication method capable of obtaining a strong effect on fading by using subcarriers in a frequency band, that is, a frequency diversity effect.
NTT DoCoMo “3GPP R1-050590 Physical Channels and Multiplexing in Evolved UTRA Downlink” June 16, 2005, p. 6-11

  Also in the communication method for obtaining the multi-user diversity effect and the communication method for obtaining the frequency diversity effect described in Non-Patent Document 1, each communication terminal device (mobile station) feeds back the propagation path state in the same manner as HSDPA, and the communication control device Scheduling is performed at (base station). However, no specific proposal has been made regarding a feedback method of propagation path conditions for efficiently switching a plurality of communication methods, a transmission method in a communication control device, a scheduling method, and the like. In order to perform wireless communication by switching and using a plurality of communication methods described in Non-Patent Document 1, an increase in the amount of feedback data of the propagation path status of each slot by each communication terminal device, and each of the communication control devices An increase in the amount of feedback data processed from the communication terminal device, a delay due to processing time, etc. are expected, a communication procedure capable of efficient and high-speed processing, a feedback data format, and communication with the communication terminal device for realizing it A control device is required.

  The present invention has been made in view of such circumstances, and a communication terminal device that efficiently feeds back information related to reception quality and transmission format to a communication control device in order to efficiently switch between a plurality of communication methods, and feedback It is an object of the present invention to provide a communication control device that switches the transmission format based on the received information and transmits data to the communication terminal device, and a wireless communication system and a communication method using these technologies.

  (1) One aspect of the communication terminal apparatus according to the present invention is a plurality of time channels specified by one or more time channels defined by a certain time length and one or more frequency channels defined by a certain frequency band. A communication terminal device that communicates with a communication control device using a slot, and that measures reception quality of a plurality of slots using a terminal-side receiving unit that receives control information from the communication control device and the received control information A reception quality measurement unit, a transmission format selection unit for selecting one transmission format from a plurality of transmission formats for allocating data to the plurality of slots based on the measured reception quality measurement results, and reception quality in the plurality of slots A feedback information generation unit that generates feedback information for notifying the communication control device of reception quality information and transmission format information specifying the selected transmission format A terminal-side transmission unit that transmits the generated feedback information to the communication control device, wherein the terminal-side reception unit receives data of the transmission format specified by the transmission format information from the communication control device. Features.

  Thus, according to one aspect of the communication terminal apparatus according to the present invention, each communication terminal apparatus measures reception quality, and specifies an appropriate transmission format when feeding back the measured reception quality to the communication control apparatus. The transmission format information can be notified. Accordingly, each communication control device can select an appropriate transmission format for the communication terminal device. Further, each communication terminal apparatus determines the transmission format of data transmitted from the communication control apparatus, so that the processing of the communication control apparatus can be reduced. Furthermore, since the feedback information transmitted from each communication terminal apparatus does not necessarily include all propagation path conditions, it is possible to reduce the transmission power of the communication terminal apparatus. Since information of an appropriate transmission format is fed back from each communication terminal apparatus, the communication control apparatus can perform more efficient data allocation.

  (2) Further, in one aspect of the communication terminal device according to the present invention, the feedback information generation unit sets a plurality of different data formats corresponding to the plurality of transmission formats, and data corresponding to the selected transmission format. A format is selected, the measured reception measurement result is edited into the selected data format to generate reception quality information, and the generated reception quality information is used as feedback information.

  In this way, the feedback information generation unit can notify the communication control apparatus of the transmission format selected on the communication terminal apparatus side according to the data format of the reception quality information. As a result, the communication control apparatus can allocate transmission data in the transmission format selected by the communication terminal apparatus, and can acquire reception quality information necessary for generating transmission data.

  (3) Further, in one aspect of the communication terminal apparatus according to the present invention, the feedback information generation unit calculates an average measurement result obtained by averaging the reception quality measurement results of a plurality of slots, and the calculated average measurement result is used as feedback information. Thus, feedback information for notifying the reception quality information and transmission format information designating the first transmission format is generated.

  In this way, the feedback information generation unit can notify the communication control apparatus of the reception quality and the transmission format using the average value of the reception quality measurement results.

  (4) In one aspect of the communication terminal apparatus according to the present invention, the feedback information generation unit uses the reception quality measurement result of each of the plurality of slots as feedback information, thereby providing the reception quality information and the second transmission format. Feedback information for notifying transmission format information for specifying is generated.

  As described above, the feedback information generation unit can notify the communication control apparatus of the reception quality and the transmission format by using the reception quality measurement result of each slot as the feedback information.

  (5) In one aspect of the communication terminal device according to the present invention, the feedback information generation unit generates reception quality information based on the measured reception quality measurement result, and the generated reception quality information, the transmission format information, It is characterized by generating feedback information including

  As described above, the feedback information generation unit can notify the communication control apparatus of the reception quality and the transmission format by generating the feedback information in which the transmission format information specifying the transmission format is added to the reception quality information. .

  (6) In one aspect of the communication terminal apparatus according to the present invention, the terminal-side receiving unit receives control information including feedback request information specifying a slot, and the reception quality measuring unit is specified in the feedback request information The feedback information generation unit generates reception quality information based on a reception quality measurement result of the designated slot.

  As described above, the reception quality measurement unit can notify the reception quality of the slot according to the request from the communication control device by measuring the reception quality of the slot designated by the communication control device.

  (7) In one aspect of the communication terminal apparatus according to the present invention, the reception quality measurement unit selects a predetermined number of slots from a plurality of slots as a feedback slot, measures the reception quality of the selected feedback slot, and The feedback information generation unit generates reception quality information based on a reception quality measurement result of the feedback slot.

  Thus, the reception quality measuring unit can measure the reception quality by limiting the number of slots, and can suppress the load.

  (8) In one aspect of the communication terminal apparatus according to the present invention, the reception quality measurement unit selects a predetermined number of slots from the measured reception quality measurement results of a plurality of slots as feedback slots, and the transmission format selection unit Selects one transmission format from a plurality of transmission formats based on the reception quality measurement result of the selected feedback slot, and the feedback information generator generates reception quality information based on the reception quality measurement result of the feedback slot. It is characterized by generating.

  As described above, the transmission format selection unit and the feedback information selection unit can perform processing based on reception quality information in a slot selected from a plurality of slots. Thereby, the processing load can be suppressed.

  (9) In one aspect of the communication terminal apparatus according to the present invention, the reception quality measurement unit selects a predetermined number of slots as feedback slots in order of good reception quality.

  Thus, according to the reception quality measuring unit, it is possible to select a slot with good reception quality and notify the communication control apparatus. As a result, the communication control apparatus can perform processing for slots with good reception quality, and efficient scheduling is possible.

  (10) In one aspect of the communication terminal apparatus according to the present invention, the reception quality measurement unit selects a predetermined number of slots in order of good reception quality, and further selects a predetermined number of slots in order of poor reception quality. And a feedback slot.

  As described above, according to the reception quality measuring unit, it is possible to notify the communication control apparatus of a slot with poor reception quality in addition to a slot with good reception quality. Thereby, the communication control apparatus can grasp | ascertain the dispersion | variation in reception quality.

  (11) In one aspect of the communication terminal apparatus according to the present invention, the reception quality measurement unit receives the propagation quality calculated from the reception signal power and the carrier signal power, or the reception data calculated from the error amount of the reception data. It is characterized by using at least one of quality.

  Thus, the reception quality measuring unit can use either the propagation path condition or the reception data quality as the reception quality.

  (12) In one aspect of the communication terminal apparatus according to the present invention, the reception quality measuring unit measures the reception quality of the same slot at a plurality of time points, and moves based on the measured reception quality at the plurality of time points. The speed is determined.

  As described above, the reception quality measuring unit can determine the reception quality in consideration of the moving speed.

  (13) In one aspect of the communication terminal apparatus according to the present invention, the plurality of transmission formats use a multi-user diversity scheme in which a communication terminal apparatus having a good propagation path condition is assigned to each slot, and a plurality of slots in the frequency direction. And at least one of a frequency diversity system for transmitting so as to obtain a diversity effect.

  As described above, efficient communication can be performed by appropriately switching a plurality of transmission formats having different characteristics.

  (14) In one aspect of the communication control device according to the present invention, a plurality of time channels specified by one or more time channels defined by a certain time length and one or more frequency channels defined by a certain frequency band A communication control apparatus that communicates with a plurality of communication terminal apparatuses using a plurality of transmission formats for assigning data to a slot, a control-side transmission unit that transmits control information to the communication terminal apparatus, and corresponding to the control information A control-side receiving unit that receives feedback information that notifies reception quality information indicating reception quality and transmission format information that designates one transmission format from the plurality of transmission formats, and based on the received feedback information, Based on the transmission format determination unit that selects the transmission format to be applied to the communication terminal device, the selected transmission format, the reception quality information, and the selected transmission format, A data allocating unit that allocates data destined for the transmission terminal device to each slot, and the control-side transmission unit uses the selected transmission format to transmit each communication terminal device allocated to each slot to the transmission destination. Is transmitted.

  As described above, according to one aspect of the communication control device according to the present invention, when each communication terminal device feeds back the reception quality, the transmission format information designating an appropriate transmission format is notified and notified. Transmission data can be generated based on the transmission format. Further, each communication terminal apparatus determines the transmission format of data transmitted from the communication control apparatus, so that the processing of the communication control apparatus can be reduced. Since information of an appropriate transmission format is fed back from each communication terminal apparatus, the communication control apparatus can perform more efficient data allocation.

  (15) Further, in one aspect of the communication control apparatus according to the present invention, the control-side receiving unit receives, as feedback information, reception quality information edited using any of a plurality of different data formats, and transmits the transmission The format determination unit selects one transmission format from a plurality of transmission formats based on the data format indicated by the reception quality information.

  As described above, the transmission format determination unit can determine the transmission format according to the data format of the reception quality information.

  (16) Furthermore, in one aspect of the communication control apparatus according to the present invention, the transmission format determination unit may determine whether the reception quality information is an average measurement result obtained by averaging the reception quality measurement results of a plurality of slots. One transmission format is selected.

  As described above, the transmission format determination unit can determine the transmission format according to the data format of the reception quality information, and can acquire the reception quality information necessary for generating the transmission data.

  (17) In one aspect of the communication control apparatus according to the present invention, the transmission format determination unit selects a second transmission format when the reception quality information is a reception quality measurement result of each of a plurality of slots. It is characterized by that.

  As described above, the transmission format determination unit can determine the transmission format according to the data format of the reception quality information, and can acquire the reception quality information necessary for generating the transmission data.

  (18) In one aspect of the communication control apparatus according to the present invention, the control-side receiving unit receives feedback information including transmission format information designating any of the plurality of transmission formats, and the transmission format determining unit includes One transmission format is selected from a plurality of transmission formats based on transmission format information included in the feedback information.

  As described above, the transmission format determination unit can determine the transmission format based on the transmission format information added to the reception quality information.

  (19) In one aspect of the communication control apparatus according to the present invention, the control-side transmission unit transmits control information including feedback request information specifying a slot position for requesting measurement of reception quality, and the control-side reception unit Receiving the feedback information for notifying the reception quality information and the transmission format information at the slot position designated in the feedback request information, the data allocating unit receiving the reception quality information at the designated slot location and the selected transmission format, Based on the above, data having the communication terminal device as a transmission destination is allocated to each slot.

  As described above, the data allocation unit can allocate slots based on the reception quality information of the slots requested by the communication control device. Thereby, efficient scheduling can be implemented.

  (20) In one aspect of the communication control apparatus according to the present invention, the control-side receiving unit selects a predetermined number of slots as a feedback slot from the plurality of slots by the communication terminal apparatus, and receives quality information in the selected feedback slot And the feedback information for notifying the transmission format information, and the data allocating unit receives data having the communication terminal device as a transmission destination based on the reception quality information in the feedback slot and the selected transmission format. It is characterized by assigning to each slot.

  In this way, the data allocation unit can allocate slots based on the reception quality information of the feedback slot selected by the communication terminal apparatus side. Thereby, efficient scheduling can be implemented.

  (21) In one aspect of the communication control apparatus according to the present invention, the plurality of transmission formats use a multi-user diversity system that allocates a communication terminal apparatus having a good propagation path condition for each slot, and a plurality of slots in the frequency direction. And at least one of a frequency diversity system for transmitting so as to obtain a diversity effect.

  As described above, efficient communication can be performed by appropriately switching a plurality of transmission formats having different characteristics.

  (22) One aspect of the wireless communication system according to the present invention is a plurality of time channels specified by one or more time channels defined by a certain time length and one or more frequency channels defined by a certain frequency band. A wireless communication system that performs communication between a communication control device and a communication control device using a slot, wherein the communication terminal device receives a control information from the communication control device, and a received control information And a reception quality measuring unit that measures reception quality of a plurality of slots, and a transmission that selects one transmission format from a plurality of transmission formats that allocate data to the plurality of slots based on the measured reception quality measurement result A format for notifying the communication control device of a format selection unit, reception quality information indicating reception quality in a plurality of slots, and transmission format information specifying the selected transmission format. A feedback information generation unit that generates feedback information; and a terminal-side transmission unit that transmits the generated feedback information to the communication control device, wherein the communication control device controls the transmission of the control information to the communication terminal device. A transmission side to be applied to the communication terminal device based on the received feedback information, a control side reception unit that receives the feedback information from the communication terminal device in correspondence with the control information A transmission format determining unit, a data allocating unit that allocates data with the communication terminal device as a transmission destination to each slot based on the selected transmission format, the reception quality information, and the selected transmission format, and The control-side transmission unit uses the selected transmission format to send data to each communication terminal device allocated to each slot as a transmission destination. And Shin, the terminal side receiving unit may receive a data transmission format specified by the transmission format information from the communication control device.

  Thus, according to one aspect of the wireless communication system according to the present invention, each communication terminal apparatus measures reception quality, and specifies an appropriate transmission format when feeding back the measured reception quality to the communication control apparatus. The transmission format information can be notified. Accordingly, each communication control device can select an appropriate transmission format for the communication terminal device. Further, each communication terminal apparatus determines the transmission format of data transmitted from the communication control apparatus, so that the processing of the communication control apparatus can be reduced. Furthermore, since the feedback information transmitted from each communication terminal apparatus does not necessarily include all propagation path conditions, it is possible to reduce the transmission power of the communication terminal apparatus. Since information of an appropriate transmission format is fed back from each communication terminal apparatus, the communication control apparatus can perform more efficient data allocation.

  (23) According to one aspect of the communication method of the present invention, a plurality of slots specified by one or more time channels defined by a certain time length and one or more frequency channels defined by a certain frequency band Is a communication method of a communication terminal device that communicates with a communication control device using the control information received from the communication control device, and using the received control information, the reception quality of a plurality of slots was measured and measured Based on the reception quality measurement result, one transmission format is selected from a plurality of transmission formats for allocating data to the plurality of slots, and reception quality information indicating reception quality in the plurality of slots and transmission for specifying the selected transmission format are selected. Generating feedback information for notifying the communication control device of the format information, transmitting the generated feedback information to the communication control device, and transmitting the transmission format information. Characterized by receiving the data of the specified transmission format from the communication control device in.

  Thus, according to the aspect of the communication method according to the present invention, each communication terminal apparatus measures reception quality, and when the measured reception quality is fed back to the communication control apparatus, transmission specifying an appropriate transmission format Format information can be notified. Accordingly, each communication control device can select an appropriate transmission format for the communication terminal device. Further, each communication terminal apparatus determines the transmission format of data transmitted from the communication control apparatus, so that the processing of the communication control apparatus can be reduced. Furthermore, since the feedback information transmitted from each communication terminal apparatus does not necessarily include all propagation path conditions, it is possible to reduce the transmission power of the communication terminal apparatus. Since information of an appropriate transmission format is fed back from each communication terminal apparatus, the communication control apparatus can perform more efficient data allocation.

  (24) According to one aspect of the communication method of the present invention, a plurality of slots specified by one or more time channels defined by a certain time length and one or more frequency channels defined by a certain frequency band A communication method of a communication control apparatus that communicates with a plurality of communication terminal apparatuses using a plurality of transmission formats for assigning data to the control terminal, wherein the control information is transmitted to the communication terminal apparatus, and the reception quality corresponds to the control information. A transmission format applied to the communication terminal device based on the received feedback information, and receiving feedback information for notifying the reception quality information indicating the transmission quality information indicating transmission format information specifying one transmission format from the plurality of transmission formats Based on the selected transmission format, the reception quality information, and the selected transmission format, the data destined for the communication terminal device is allocated to each slot. And Te, by using the transmission format and said selected, and transmits the data of which destination is the communication terminal apparatus assigned to each slot.

  Thus, according to one aspect of the communication method according to the present invention, when each communication terminal device feeds back the reception quality, the transmission format information designating an appropriate transmission format is notified and notified. Transmission data can be generated based on the transmission format. Further, each communication terminal apparatus determines the transmission format of data transmitted from the communication control apparatus, so that the processing of the communication control apparatus can be reduced. Since information of an appropriate transmission format is fed back from each communication terminal apparatus, the communication control apparatus can perform more efficient data allocation.

  (25) One aspect of the communication method according to the present invention is a plurality of slots specified by one or more time channels defined by a certain time length and one or more frequency channels defined by a certain frequency band. A communication method of a wireless communication system that performs communication between a communication control device and a communication control device using the communication terminal device, wherein the communication terminal device receives control information from the communication control device, and uses the received control information , Measure the reception quality of a plurality of slots, select one transmission format from a plurality of transmission formats to assign data to the plurality of slots based on the measured reception quality measurement results, and indicate the reception quality in the plurality of slots Feedback information for notifying the communication control device of reception quality information and transmission format information specifying the selected transmission format is generated, and the generated feedback information is generated. Is transmitted to the communication control apparatus, the communication control apparatus transmits the control information to the communication terminal apparatus, and receives the feedback information from the communication terminal apparatus in response to the control information. Based on feedback information, a transmission format to be applied to the communication terminal device is selected. Based on the selected transmission format, the reception quality information, and the selected transmission format, data destined for the communication terminal device is assigned to each slot. And the communication control apparatus transmits data to which each communication terminal apparatus allocated to each slot is a transmission destination using the selected transmission format, and the communication terminal apparatus is designated by the transmission format information. The transmission format data is received from the communication control device.

  Thus, according to the aspect of the communication method according to the present invention, each communication terminal apparatus measures reception quality, and when the measured reception quality is fed back to the communication control apparatus, transmission specifying an appropriate transmission format Format information can be notified. Accordingly, each communication control device can select an appropriate transmission format for the communication terminal device. Further, each communication terminal apparatus determines the transmission format of data transmitted from the communication control apparatus, so that the processing of the communication control apparatus can be reduced. Furthermore, since the feedback information transmitted from each communication terminal apparatus does not necessarily include all propagation path conditions, it is possible to reduce the transmission power of the communication terminal apparatus. Since information of an appropriate transmission format is fed back from each communication terminal apparatus, the communication control apparatus can perform more efficient data allocation.

  (26) In one aspect of the wireless communication system according to the present invention, the feedback information generation unit calculates an average measurement result obtained by averaging the reception quality measurement results of a plurality of slots, and receives each of the plurality of slots. One of the quality measurement results and feedback information is generated as reception quality information, and when the feedback information is the average measurement result, the transmission format determination unit selects a frequency diversity method as the transmission format, and the feedback information Is the measurement result, the multi-user diversity method is selected as the transmission format.

  In this way, the communication terminal apparatus can notify the communication control apparatus of the reception quality and the transmission format by editing the reception quality measurement result in the data format of the average measurement result or the reception quality measurement result of each slot. . In addition, the communication control apparatus can determine the transmission format according to the data format of the reception quality information, and can acquire the reception quality information necessary for generating the transmission data. Thereby, the amount of feedback information can be reduced.

  According to the present invention, the communication terminal apparatus feeds back information related to reception quality and transmission format to the communication control apparatus in a predetermined format, so that the communication control apparatus efficiently uses a plurality of transmission formats based on the fed back information. It is possible to transmit data to the communication terminal device by switching between them.

  Next, embodiments of the present invention will be described with reference to the drawings.

  In this specification, a communication control device that controls communication between a plurality of communication terminal devices and a wireless communication system that performs communication between the communication terminal devices under the control of the communication control device will be described as an example. The wireless communication system uses a multicarrier communication system.

  In each embodiment described below, the wireless communication system will be described using a 1-cell repetitive OFDM / (TDMA, FDMA) communication scheme. In a wireless communication system, a communication control apparatus performs wireless communication with a plurality of communication terminal apparatuses, and adaptively allocates resources in a frame to each communication terminal apparatus in order to transmit a data packet to each communication terminal apparatus. Specifically, the communication control apparatus assigns data to be transmitted to a plurality of slots constituting the frame. In this specification, the frame is composed of a plurality of slots as shown in FIG. A slot is specified by one or more time channels defined by a certain time length and one or more frequency channels defined by a certain frequency band.

  Each communication terminal apparatus in the wireless communication system receives known information included in control information transmitted from the communication control apparatus, and measures reception quality. Each communication terminal apparatus creates feedback information based on the measured reception quality. At this time, each communication terminal apparatus can request the format of the transmission data by notifying the transmission data format (transmission format) transmitted from the communication control apparatus to itself together with the reception quality as feedback information. . The communication control apparatus performs resource (slot) allocation to each communication terminal apparatus based on feedback information from each transmission terminal apparatus and the state of the transmission data buffer of each communication terminal apparatus in the communication control terminal. At this time, the communication control device selects an appropriate transmission format for each communication terminal device according to the transmission format notified from each communication terminal device, and performs resource allocation for transmission data.

  Each embodiment will be described using a wireless communication system including a communication control device and a communication terminal device. In the drawing, although one communication terminal device is shown, there are a plurality of communication terminal devices, and the communication control device can transmit and receive signals to and from the plurality of communication terminal devices.

(First embodiment)
Hereinafter, an embodiment according to the first embodiment will be described with reference to the drawings. FIG. 1 is a block diagram illustrating a schematic configuration of a communication control apparatus according to the first embodiment. FIG. 2 is a block diagram illustrating a schematic configuration of the communication terminal apparatus according to the first embodiment. In the present embodiment, a description is given using a wireless communication system including the communication control device 100 and the communication terminal device 200. The communication control apparatus 100 includes a transmission format determination unit 101, a data allocation unit 102, a data modulation unit 103, an S / P (Serial / Parallel) conversion unit 104, an IFFT (Inverse Fast Fourier Transform) unit 105, a GI (Guard Interval) insertion unit 106, D / A (Digital / Analog) conversion unit 107, radio transmission unit 108, antenna unit 109, radio reception unit 110, A / D (Analog / Digital) conversion unit 111, GI A removal unit 112, an FFT (Fast Fourier Transform) unit 113, a P / S (Parallel / Serial) conversion unit 114, and a data demodulation unit 115 are provided.

  The transmission format determination unit 101 determines the transmission format based on feedback information transmitted from each communication terminal device 200. The feedback information is information for notifying the reception quality measurement result measured by the communication control apparatus 100 and the transmission format.

  The data allocation unit 102 allocates resources (slots) in the communication frame to packet data to be transmitted to each communication terminal device 200. The data modulation unit 103 modulates the transmission signal. The S / P converter 104 converts the serial signal of the transmission signal into a parallel signal. The IFFT unit 105 performs an IFFT process on the transmission signal. The GI insertion unit 106 inserts a guard interval into the transmission signal. The D / A converter 107 converts the digital transmission signal into an analog transmission signal. The wireless transmission unit 108 transmits an analog transmission signal. The antenna unit 109 exchanges radio transmission signals and radio reception signals. The wireless reception unit 110 receives an analog reception signal. The A / D converter 111 converts an analog reception signal into a digital reception signal. The GI removal unit 112 removes the GI of the received signal. The FFT unit 113 performs an FFT process on the received signal. The P / S converter 114 converts the received parallel signal into a serial signal. The data demodulator 115 demodulates the received signal.

  The communication terminal apparatus 200 includes a data modulation unit 201, an S / P conversion unit 202, an IFFT unit 203, a GI insertion unit 204, a D / A conversion unit 205, a wireless transmission unit 206, an antenna unit 207, a wireless reception unit 208, an A / P A D conversion unit 209, a GI removal unit 210, an FFT unit 211, a P / S conversion unit 212, a data demodulation unit 213, a reception quality measurement unit 214, a transmission format selection unit 215, and a feedback information generation unit 216.

  The data modulation unit 201 modulates the transmission signal. The S / P converter 202 converts the serial signal of the transmission signal into a parallel signal. The IFFT unit 203 performs an IFFT process on the transmission signal. The GI insertion unit 204 inserts a GI into the transmission signal. The D / A conversion unit 205 converts the digital transmission signal into an analog transmission signal. The wireless transmission unit 206 transmits an analog transmission signal. The antenna unit 207 transfers wireless transmission signals and wireless reception signals. The wireless reception unit 209 receives an analog reception signal. The A / D conversion unit 209 converts the analog reception signal into a digital reception signal. The GI removal unit 210 removes the GI of the received signal. The FFT unit 211 performs an FFT process on the received signal. The P / S converter 212 converts the received parallel signal into a serial signal. The data demodulator 213 demodulates the received signal.

  The reception quality measurement unit 214 measures the propagation path condition and reception quality of the reception signal. In the present embodiment, the reception quality of each slot is measured using the control signal received from the communication control apparatus 100.

  The transmission format selection unit 215 selects one transmission format from a plurality of transmission formats in which data is allocated to a plurality of slots constituting a frame, based on the reception quality measurement result measured by the reception quality measurement unit 214.

  The feedback information generation unit 216 generates feedback information based on the measurement result (reception quality measurement result) measured by the reception quality measurement unit 214 and the transmission format selected by the transmission format selection unit 215. The feedback information is information for notifying reception quality information indicating reception quality in a plurality of slots and transmission format information specifying a selected transmission format. In the present embodiment, the feedback information generation unit 216 sets a plurality of different data formats corresponding to a plurality of transmission formats, selects a data format corresponding to the transmission format selected by the transmission format measurement unit 215, and measures reception quality. The reception measurement result measured by the unit 214 is edited into the selected data format to generate reception quality information, and the generated reception quality information is used as feedback information. This will be described later with reference to FIG.

  In the following description, in the communication control device 100, the data modulation unit 103, the S / P conversion unit 104, the IFFT unit 105, the GI insertion unit 106, the D / A conversion unit 107, and the wireless transmission unit 108 are controlled. 116, the wireless reception unit 110, the A / D conversion unit 111, the GI removal unit 112, the FFT unit 113, the P / S conversion unit 114, and the data demodulation unit 115 are defined as the control side reception unit 117. In the communication terminal device 200, the data modulation unit 201, the S / P conversion unit 202, the IFFT unit 203, the GI insertion unit 204, the D / A conversion unit 205, and the wireless transmission unit 206 are referred to as a terminal side transmission unit 217. The radio reception unit 208, A / D conversion unit 209, GI removal unit 210, FFT unit 211, P / S conversion unit 212, and data demodulation unit 213 will be described as the terminal side reception unit 218. The control-side transmission unit 116 and the terminal-side transmission unit 217 have a function of modulating and converting transmission data according to the transmission format, and transmitting the data to the communication destination via the antenna unit 109. The receiving unit 218 has a function of receiving received data from the communication destination via the antenna unit 109 and converting and modulating the received data according to the transmission format. Further, the terminal side reception unit 218 outputs the reception data subjected to the FTT processing by the FTT unit 211 to the reception quality measurement unit 214.

  Next, the operation of the wireless communication system of this embodiment will be described with reference to the sequence diagram according to this embodiment of FIG. FIG. 3 is a diagram illustrating, in time series, an example of exchange of wireless data between the communication control device and the communication terminal device according to the first embodiment and their respective operations. The wireless communication system is a system including one communication control apparatus 100 and a plurality of communication terminal apparatuses 200, and the diagram shown in FIG. 3 shows a state between one of the plurality of communication terminal apparatuses 200 and the communication control apparatus 100. However, the same operation is performed with respect to the other communication terminal devices 200, and wireless communication with the communication control device 100 is performed.

  First, the communication control apparatus 100 transmits transmission data including control information to the communication terminal apparatus 200 (step S11). The control information includes known information that the communication terminal device 200 already knows. The transmission data is transmitted to each communication terminal apparatus 200 in the frame configuration shown in FIG. 10, and each slot includes pilot symbols, transmission power information, and modulation scheme information, which are known information. However, in the case where each slot is always transmitted with constant power without performing power control of the downlink communication frame, it is not always necessary to include transmission power information in each slot. In the present embodiment, a case where power control of downlink wireless communication is not performed will be described.

  The communication terminal device 200 receives transmission data including control information from the communication control device 100. The terminal-side transmission unit 217 performs FFT processing on the transmission data and outputs it to the reception quality measurement unit 214. The reception quality measurement unit 214 measures the reception quality of each slot (step S12). The reception quality measuring unit 214 measures the reception quality (propagation path condition) based on the known control information included in the slot. In the present embodiment, the reception quality measurement unit 214 describes a case where a propagation path condition (propagation path quality) indicating a propagation path quality (environment) is measured as reception quality, but other reception qualities may be used. .

  Specifically, SINR (Signal to Interference and Noise Ratio), SNR (Signal to Interference Ratio), SIR (Signal to Interference Ratio), CINR (Carrier to Interference and NoiseR). (Carrier to Interference Ratio), propagation quality calculated from received signal power and carrier signal power such as RSSI (Received Signal Strength Indicator), or BER (Bit Error Rate), PER (Packet Error Rate), BLER It is possible to use an index indicating the received data quality calculated from the received data error amount, such as (Block Error Rate). The reception quality measuring unit 214 continuously measures the same frequency slot in the time axis direction. Thereby, the reception quality measuring unit 214 can measure a temporal change in the propagation path condition, and can also be used as an index of the moving speed of the communication terminal apparatus 200.

  Next, the transmission format selection unit 215 of the communication terminal device 200 selects one transmission format from a plurality of transmission formats based on the reception quality measurement result measured by the reception quality measurement unit 214 (step S13). The feedback information generation unit 216 generates feedback information based on the transmission format selected by the transmission format selection unit 215 and the reception quality measurement result measured by the reception quality measurement unit 214 (step S14). Feedback information generated by the uplink wireless communication is notified to the communication control apparatus 100 (step S15). A more specific operation of generating feedback information by communication terminal apparatus 200 will be described with reference to FIG. FIG. 4 is a diagram illustrating an example of an operation in which the communication terminal device 200 according to the present embodiment generates feedback information.

  First, the reception quality measurement unit 214 of the communication terminal apparatus 200 determines whether feedback request information from the communication control apparatus 100 has been notified (step S21). The feedback request information is included in the control information received by the terminal side receiving unit 217, but may be a method notified by the control information received this time, or the feedback request information notified by the previously received control information is used. The method is also possible.

  The feedback request information designates a slot for measuring reception quality (propagation channel quality, reception data quality, moving speed, etc.), and feeds back reception quality information based on the reception quality measurement result obtained by measuring the reception quality of the designated slot. It is information requesting that. That is, the feedback request information is information that designates which slot of a plurality of slots is to be notified of the reception quality measurement result as feedback information. The slot requested (designated) by the feedback request information is designated as the designated slot. The feedback information specifies some of the slots F1 to F12 in the frame configuration shown in FIG. More specifically, a method of specifying four consecutive slots from F1 to F4 or three consecutive slots of F1, F5, and F9 can be considered. Thereby, the communication control apparatus 100 can acquire the reception quality information of the slot to which the communication terminal apparatus 200 is to be allocated (slot to be allocated). In addition, it is possible to suppress the amount of reception quality information.

  When the feedback request information is notified from the communication control apparatus 100 (YES in step S21), the communication terminal apparatus 200 measures the reception quality with respect to the slot (designated slot) at the designated position (step S22).

  Next, in communication terminal apparatus 200, transmission format selection section 215 selects one transmission format from a plurality of transmission formats based on the reception quality measurement result of the designated slot measured by reception quality measurement section 214 (step S23). ). The transmission format selection unit 215 compares the reception quality measurement result with a predetermined threshold value to determine whether the reception quality is good. When there are two or more transmission formats, the reception quality is compared using a multi-stage threshold value, and the transmission format is selected.

  In the present embodiment, a multi-user diversity format and a frequency diversity format are used as transmission formats. The multi-user diversity format applies a modulation parameter corresponding to the propagation path condition of each communication terminal apparatus 200, assigns each slot to the communication terminal apparatus 200 with good propagation path condition, and performs packet transmission, thereby This is a method for obtaining a multi-user diversity effect that improves the throughput. The modulation parameter is a parameter that specifies at least one of a modulation scheme, a coding rate, and a spreading factor. Including. The frequency diversity format is a method for obtaining a frequency diversity effect in downlink wireless communication by using a plurality of slots in the frequency axis direction during scheduling. The transmission format is not limited to the above two, and the present invention is applied to a plurality of transmission formats, for example, a plurality of different transmission formats such as the first transmission format and the second transmission format. be able to. A specific example of the transmission method will be described later with reference to FIGS.

  The transmission format selection unit 215 selects the multi-user diversity format when the propagation path condition is good in the designated slot. When the propagation path condition is poor, or the movement speed of the communication terminal device 200 is fast, the transmission path condition changes. If the frequency is severe, select the frequency diversity format. The transmission format selection unit 215 selects a transmission format depending on whether or not predetermined reception quality is satisfied. The transmission format selection unit 215 normally selects the multi-user diversity format, and when the propagation path condition is bad, or when the movement speed of the communication terminal apparatus 200 is fast and the propagation path condition varies greatly. The transmission format may be changed. By changing the transmission format, wireless transmission / reception is performed with a frequency diversity effect in downlink wireless communication using a plurality of slots in the frequency axis direction during scheduling in the communication control apparatus 100 according to the propagation path condition.

  The feedback information generation unit 216 generates feedback information based on the reception quality measurement result measured by the reception quality measurement unit 214 and the transmission format selected by the transmission format selection unit 215 (step S24). The feedback information generation unit 216 selects a data format corresponding to the transmission format selected by the transmission format selection unit 215 from a plurality of data formats, edits the reception quality measurement result of the selected data format, and generates feedback information. In the present embodiment, as a data format of reception quality information included in feedback information, a measurement value format for generating feedback information by associating a reception quality measurement result with a position (slot number) of a designated slot, and reception of the designated slot An average measurement result is calculated by averaging the quality measurement results, and a data format different from the average value format for generating the calculated average measurement results as feedback information is used. However, the slot number and the reception quality information of the designated slot are arranged under certain conditions, for example, in order from the slot with the lowest frequency in the frequency axis direction (from the F1 side of the frequency slot shown in FIG. 10). It is also possible to substitute the association, and the amount of information indicating the slot number can be reduced.

  Therefore, when the transmission format selection unit 215 selects the multi-user diversity format, the feedback information generation unit 216 generates feedback information in the measurement value format by associating the measured reception quality measurement result with the slot number of the designated slot. When the frequency diversity format is selected, the average measurement result is calculated using the reception quality measurement result and the number of designated slots, and the average measurement result is combined with the position (slot number) of the designated slot from which the average value is calculated. Generate feedback information in the form of average values.

  Further, the feedback information does not necessarily return the reception quality measurement result as described above, but is a data obtained by quantizing the reception quality measurement result, or a modulation scheme that can be transmitted / received with the measured reception quality, or an information bit indicating the modulation scheme Alternatively, it is possible to notify the fluctuation value with the reception quality measurement result measured at the previous measurement opportunity and notified to the communication control apparatus 100 or the information bit obtained by quantizing the fluctuation value. Thereby, it contributes to the reduction of the data amount of uplink wireless communication, and furthermore, the power consumption of the communication terminal apparatus 200 can be reduced.

  If feedback information is not notified from the communication control apparatus 100 (NO in step S21), the reception quality of all slots is measured (step S25). When the feedback request information is not notified, the communication terminal apparatus 200 can set a slot for measuring the propagation path state in advance in order to reduce the measurement amount and the data processing amount. Based on the measured reception quality measurement results of all slots, the reception quality measurement unit 214 notifies the communication control apparatus 100 of reception quality information, that is, a slot that includes reception quality information related to the reception quality measurement results in feedback information ( A feedback slot and a selection slot are selected (step S26). For example, one or more slot groups capable of selecting a slot having a good channel condition to an upper five slot, or a slot having a good channel condition to an upper four slot and a lower one slot, or the most efficient modulation scheme that can be transmitted. The feedback slot can be selected based on the conditions such as When the number of slots to be fed back is designated from all the measured slots from the communication control apparatus 100, the designated number of slots is selected according to a predetermined condition and set as a feedback slot. By notifying only slots with good reception quality, the communication control apparatus can perform scheduling efficiently. In addition, by notifying a slot with poor reception quality, the communication control apparatus can grasp the variation in reception quality.

  The selection of the feedback slot can be performed both before measuring the reception quality, after measuring the reception quality, before measuring the reception quality, and after. After measuring the reception quality of all the slots, a slot with good reception quality is selected as a feedback slot. A feedback slot reflecting the reception quality can be selected. Further, after selecting a feedback slot in advance, the reception quality is measured. For example, this is effective when the reception quality can be predicted from the previous measurement result. Furthermore, it is also possible to set a range for measuring reception quality among a plurality of slots, measure the reception quality, and then select a feedback slot based on the reception quality. By first selecting a predetermined range from the plurality of slots, it is possible to reduce the load for measuring the reception quality.

  The reception quality measurement unit 214 notifies the transmission format selection unit 215 of the slot number of the selected feedback slot and the reception quality measurement result. Also, the reception quality measurement result 214 indicates that, when a slot for measuring a propagation path condition is set in advance, a feedback slot may be selected from a plurality of slots whose reception quality has been measured, or a transmission format for all the set slots The selection unit 215 may be notified. Further, the feedback slot may be the entire measured slot.

  The transmission format selection unit 215 selects one transmission format from a plurality of transmission formats based on the reception quality measurement result of the feedback slot selected by the reception quality measurement unit 214 (step S27). The transmission format is the same as described above.

  The feedback information generation unit 216 generates feedback information based on the reception quality measurement result measured by the reception quality measurement unit 214 and the transmission format selected by the transmission format selection unit 215 (step S28). When the data format is the multi-user diversity format, it becomes a measurement value format that reports the reception quality measurement result of all the measured slots or the reception quality measurement result of the selected feedback slot, and the measured reception quality measurement result of each slot is displayed in the slot position. The feedback information is generated in correspondence with the information (slot number) indicating. When the data format is frequency diversity format, it becomes an average value format that reports the average measurement result of the feedback slot, averages the reception quality measurement results of all the measured slots or all the measured feedback slots, and averages the average measurement result and the feedback slot Are generated as feedback information. As described above, in the measurement value format, the feedback information generation unit 216 generates the reception quality measurement result of all slots (or feedback slots) and the slot numbers indicating all slots (or feedback slots) as feedback information, and uses the average value format. In, at least one of the information indicating the average reception quality measurement results in a plurality of slots, the number of slots from which the average value was calculated, or the slot number indicating the slot position from which the average value was calculated, and the average Feedback information is generated by combining the measurement results.

  Next, the operation of the communication control apparatus 100 that has received the feedback information will be described with reference to FIG. The communication control apparatus 100 receives the feedback information (step S15) transmitted from each communication terminal apparatus 200, and the transmission format determination unit 101 determines the transmission format and the communication terminal apparatus to each communication terminal apparatus according to the data format of the feedback information. The transmission data modulation method for each 200 is determined (step S16). Specifically, the data format of the feedback information transmitted from communication terminal apparatus 200 is determined, and the transmission format is selected based on the determined data format. In the present embodiment, the feedback information in which the data format of the reception quality information is the measurement value format selects the multi-user diversity format, and the feedback information in which the data format of the reception quality information is the average value format selects the frequency diversity format.

  Next, the data allocation unit 102 allocates transmission data to each slot based on the reception quality measurement result included in the feedback information and the transmission format determined by the transmission format determination unit 101 (step S17). FIG. 5 and FIG. 6 are diagrams illustrating an example of a frequency diversity format slot configuration. In the frequency diversity format, a plurality of slots are allocated to the same time slot in the frequency direction so as to obtain a frequency diversity effect. FIG. 7 is a diagram showing an example of multi-user diversity format slot assignment. In the multi-user diversity format, the communication terminal device 200 to be assigned for each single slot is determined, and slots for performing downlink wireless communication are assigned.

  When the transmission format is the frequency diversity format, the data allocation unit 102 divides one slot in the time axis direction based on the average measurement value, as shown in an example in FIG. 5 and FIG. Allocate transmission data for the destination. FIG. 5 shows an example in which the entire band is used in the transmission format in which slots are allocated in the frequency diversity format. By allocating data packets having a low coding rate as transmission symbols in the frequency direction over the entire frequency band, the frequency axis direction This is a form that improves the resistance to fluctuations in the channel state of frequency selectivity. FIG. 6 is an example in which a part of the frequency band is used and is allocated in a non-consecutive manner. Propagation of frequency selectivity in the frequency axis direction by arranging a plurality of single slots in which the transmission symbols are arranged in the frequency direction. It is a form that improves resistance to changes in road conditions. In addition, when the transmission format is the multi-user diversity format, the data allocation unit 102 allocates transmission data for each slot as shown in FIG. FIG. 7 shows a format for determining the communication terminal device 200 to be assigned for each single slot in consideration of the propagation path status, transmission buffer status, data transmission priority, quality assurance and the like. Further, the data allocation unit 102 determines a modulation parameter based on information fed back from each communication terminal apparatus 200.

  The control-side transmitter 116 transmits the allocation information and the transmission data in which the communication terminal device is allocated to each slot (step S18).

  In the above description, the communication control apparatus 100 selects a transmission format corresponding to the data format of the feedback information transmitted from each communication terminal apparatus 200, assigns the transmission data to be transmitted to each communication terminal apparatus 200 to each slot, and downloads it. A mode of performing directional wireless transmission has been described. The feedback cycle in which the communication control apparatus acquires feedback information from the communication terminal device 200 is the same as the slot length cycle in the shortest interval. The communication control apparatus 100 can perform the slot allocation cycle at the same cycle as the feedback cycle. On the other hand, for simplification and reduction of operating power, the communication control apparatus 100 does not necessarily perform slot allocation in the same cycle as the feedback cycle.

  As described above, in this embodiment, each communication terminal apparatus measures the reception quality (propagation channel state) and notifies the feedback information in a predetermined data format when feeding back to the communication control apparatus. The specified transmission format information can be notified. As a result, each communication control device can select an appropriate transmission format for the communication terminal device, and the communication control device can use the data format of the reception quality measurement result required for data transmission to receive quality. Can be notified. Further, each communication terminal apparatus determines the transmission format of data transmitted from the communication control apparatus, so that the processing of the communication control apparatus can be reduced. Furthermore, since the feedback information transmitted from each communication terminal device does not necessarily include all propagation path conditions, it is possible to reduce the transmission power of the communication terminal device by limiting slots such as designated slots or feedback slots. It is. Since information of an appropriate transmission format is fed back from each communication terminal apparatus, the communication control apparatus can perform more efficient data allocation.

(Second Embodiment)
In the second embodiment, the basic system is the same as that of the first embodiment, but an aspect in which the method of notifying the transmission format information of each communication terminal apparatus at the time of feedback transmission will be described.

  Hereinafter, the radio | wireless communications system of 2nd Embodiment which concerns on this invention is demonstrated. In the second embodiment, as in the first embodiment, the wireless communication system will be described using a one-cell repetitive OFDM / (TDMA, FDMA) system.

  Also in the second embodiment, when the communication control apparatus 100 receives and demodulates feedback information created based on the reception quality measurement result measured by each communication terminal apparatus 200, the communication control apparatus 100 receives the feedback information. The transmission format of the transmission data transmitted by each communication terminal device 200 can be determined based on the above. In the second embodiment, the communication terminal device 200 adds transmission format information specifying the transmission format to the feedback information, and the communication control device 100 transmits based on the transmission format information added (included) to the feedback information. This is a mode for judging the format.

  The communication control apparatus 100 according to the present embodiment has the same configuration as that of FIG. 1 and applies the same block configuration as that of the first embodiment. The difference from the first embodiment is that the feedback information input to the transmission format determination unit 101 includes transmission format information specifying a transmission format as additional information. The transmission format determination unit 101 determines the transmission format of transmission data that the communication control device 100 transmits to each communication terminal device 200 based on the transmission format information included in the feedback information notified from each communication terminal device 200.

  The communication terminal apparatus 200 of this embodiment has the same configuration as that in FIG. 2 and applies the same block configuration as that of the first embodiment. In communication terminal apparatus 200, reception quality measurement section 214 measures the reception quality of the slot, and transmission format selection section 215 selects the transmission format based on the measured reception quality measurement result. The feedback information generation unit 216 generates reception quality information based on the reception quality measurement result measured by the reception quality measurement unit 214, and generates transmission format information indicating the transmission format selected by the transmission format selection unit 215. Feedback information including the reception quality information and the generated transmission format information is generated. The transmission format information may be information specifying the transmission format, and the transmission format is specified by a numerical value, a character string, or other data determined with the communication control device 100.

  Hereinafter, the operation of the wireless communication system of the present embodiment will be described with reference to the sequence diagram according to the present embodiment of FIG. FIG. 8 is a diagram showing, in time series, an example of exchange of wireless data between the communication control device and the communication terminal device according to the second embodiment and their respective operations. The wireless communication system is a system including one communication control apparatus 100 and a plurality of communication terminal apparatuses 200. FIG. 8 shows a state between one of the plurality of communication terminal apparatuses 200 and the communication control apparatus 100. However, the same operation is performed for the other communication terminal devices 200, and wireless communication with the communication control device 100 is performed.

  First, the communication control apparatus 100 transmits transmission data including control information to the communication terminal apparatus 200 (step S31). The control information includes known information that the communication terminal device 200 already knows. The transmission data is transmitted to each communication terminal apparatus 200 in the frame configuration shown in FIG. 10, and each slot includes pilot symbols, transmission power information, and modulation scheme information, which are known information. In the second embodiment, a case where power control of downlink wireless communication is not performed will be described.

  The communication terminal device 200 receives transmission data including control information from the communication control device 100. The terminal side transmission unit 217 performs FFT processing on the transmission data and outputs the result to the reception quality measurement unit 214, and the reception quality measurement unit 214 measures the reception quality of each slot (step S32). As the reception quality, the same index as that shown in the first embodiment can be applied. In the present embodiment, the case where the reception quality measurement unit 214 measures the propagation path state as the reception quality will be described. Reception quality measuring section 214 measures the propagation path condition based on known information in pilot symbols included in the slot.

  Next, the transmission format selection unit 215 of the communication terminal device 200 selects one transmission format from a plurality of transmission formats based on the reception quality measurement result measured by the reception quality measurement unit 214 (step S33). The feedback information generation unit 216 generates reception quality information based on the reception quality measurement result measured by the reception quality measurement unit 214 (step S34). Also, transmission format information specifying the transmission format selected by the transmission format selection unit 215 is created, and the created transmission format information is added to the generated reception quality information to generate feedback information (step S35). The feedback information generated by the uplink wireless communication is notified to the communication control apparatus 100 (step S36). A more specific operation of generating feedback information by communication terminal apparatus 200 will be described below according to the flow shown in FIG. FIG. 9 is a diagram illustrating an example of an operation in which the communication terminal device according to the present embodiment generates feedback information.

  First, the reception quality measurement unit 214 of the communication terminal apparatus 200 determines whether feedback request information is notified from the communication control apparatus 100 (step S41). The feedback request information, the designated slot included in the feedback request information, and the feedback request information notification method are the same as in the first embodiment. When the feedback request information is notified from the communication control apparatus 100 (YES in step S41), the communication terminal apparatus 200 measures the reception quality with respect to the slot (designated slot) at the designated position (step S42).

  Next, in communication terminal apparatus 200, transmission format selection section 215 selects one transmission format from a plurality of transmission formats based on the reception quality measurement result of the designated slot measured by reception quality measurement section 214 (step S43). ). Similar to the first embodiment, the transmission format selection unit 215 can determine whether the reception quality is good by comparing the reception quality measurement result with a predetermined threshold. In the present embodiment, a multi-user diversity format and a frequency diversity format are used as transmission formats, as in the first embodiment.

  The transmission format selection unit 215 selects the multi-user diversity format when the propagation path condition is good in the designated slot. When the propagation path condition is poor, or the movement speed of the communication terminal device 200 is fast, the transmission path condition changes. If the frequency is severe, select the frequency diversity format. The transmission format selection unit 215 normally selects the multi-user diversity format, and when the propagation path condition is bad, or when the movement speed of the communication terminal apparatus 200 is fast and the propagation path condition varies greatly. The transmission format may be changed. By changing the transmission format, wireless transmission / reception is performed with a frequency diversity effect in downlink wireless communication using a plurality of slots in the frequency axis direction during scheduling in the communication control apparatus 100 according to the propagation path condition.

  The feedback information generation unit 216 generates feedback information based on the reception quality measurement result measured by the reception quality measurement unit 214 and the transmission format selected by the transmission format selection unit 215 (step S44). Feedback information generating section 216 generates reception quality information by associating the designated slot with the reception quality measurement result of each designated slot. Further, transmission format information for specifying the transmission format is created and added to the generated reception quality information to generate feedback information (step S45). In the present embodiment, since the transmission format is not notified using the data format for notifying the communication control apparatus 100 of the reception quality measurement result, the data format of the feedback information is the communication control apparatus 100, the communication terminal apparatus 200, and the like. It is possible to use the data format agreed between the two. Communication terminal apparatus 200 can select a data format in accordance with the reception quality status (channel status) by including information specifying the data format in the feedback information. As a result, the amount of feedback information can be suppressed. For example, a measurement value format is used in which feedback information is generated by associating information indicating the slot position of each slot with the propagation path status information of each slot. Alternatively, if the propagation path conditions are almost the same between the designated slots and there is no need to change the transmission format (transmission modulation method), the average value obtained by averaging the reception quality measurement results of all the designated slots is calculated and calculated. An average value format is used in which the average value and the slot number of the designated slot are used as feedback information. When the average value format is used, the amount of information can be suppressed compared to when the measurement value format is used.

  The feedback information includes (1) data obtained by quantizing the average measurement value or the reception quality measurement result, and (2) information indicating a modulation parameter (modulation method) that can be transmitted / received in the propagation path state with the average measurement value or the method. (3) Notifying by data such as a fluctuation value with the propagation path status data measured and notified to the communication control apparatus 100 before the feedback information is notified this time, or an information bit obtained by quantizing the fluctuation value. Can do. Furthermore, in communication terminal apparatus 200, information indicating a designated slot (slot number), information indicating an average of a plurality of specified slots (information indicating an average measurement value, information indicating a data format), or Feedback information can also be generated by associating information (slot number) indicating the slot position at which the average measurement value is calculated with the average measurement value.

  Furthermore, by specifying different transmission formats in the transmission format information when the propagation path condition is bad in the designated slot, or when the movement speed of the communication terminal apparatus 200 is fast and the propagation path condition fluctuation is severe, the communication format is designated. It is possible to notify the control apparatus 100 of the propagation path status. The transmission format information can also specify a transmission format using bits. For example, when the bit is ON “1”, the multi-user diversity format can be specified, and when the bit is OFF “0”, the frequency diversity format can be specified. Further, when there are three or more transmission formats, it can be dealt with by increasing the number of display bits.

  If feedback information is not notified from the communication control apparatus 100 (NO in step S41), the reception quality of all slots is measured (step S46). When the feedback request information is not notified, it is possible to set a slot for measuring the propagation path state in advance in the communication terminal device 200 in order to reduce the measurement amount and the data processing amount. The reception quality measurement unit 214 notifies the communication control apparatus 100 of the reception quality based on the measured reception quality measurement results of all slots, that is, a slot (feedback slot, selection slot) that includes the reception quality measurement result in the feedback information. ) Is selected (step S47). The reception quality measurement unit 214 can select a slot to be fed back as in the first embodiment.

  The reception quality measurement unit 214 notifies the transmission format selection unit 215 of the slot number of the selected feedback slot and the reception quality measurement result. In the reception quality measurement result 214, when a slot for measuring a propagation path condition is selected in advance, a feedback slot may be selected from a plurality of slots whose reception quality has been measured, or a transmission format selection unit for all the selected slots. You may notify to 215. Further, the feedback slot may be the entire measured slot.

  The transmission format selection unit 215 selects one transmission format from a plurality of transmission formats based on the reception quality measurement result of the slot (feedback slot) selected by the reception quality measurement unit 214 (step S48). The transmission format is the same as described above.

  The feedback information generation unit 216 generates feedback information based on the reception quality measurement result measured by the reception quality measurement unit 214 and the transmission format selected by the transmission format selection unit 215 (step S49). When notifying the reception quality measurement result of all feedback slots, the reception quality measurement result of the feedback slot is associated with information (slot number) indicating the position of each slot.

  Similarly to step S44 described above, when the channel conditions are almost the same between the slots that feed back information and there is no need to change the transmission modulation scheme, the average of the reception quality measurement results of a plurality of slots is averaged. The measurement result is associated with information indicating the average slot position. In addition, similarly to step S44, reception quality information is generated, transmission format information specifying a transmission format is generated, added to the reception quality information, and feedback information is generated (step S50).

  Next, the operation of the communication control apparatus 100 that has received the feedback information transmitted from each communication terminal apparatus 200 will be described with reference to FIG. The communication control apparatus 100 receives the feedback information, and the transmission format determination unit 101 determines the transmission format to each communication terminal apparatus 200 based on the transmission format information added to the feedback information (step S37). In an example in which a bit is added as transmission format information, the transmission format is determined based on whether the bit is ON “1” or OFF “0”. In this embodiment, the transmission format to be selected is selected from the multi-user diversity format and the frequency diversity format. A specific example of the transmission format is the same as that described with reference to FIGS. 5 to 7 in the first embodiment.

  The communication control device 100 selects a transmission format corresponding to the transmission format information notified from each communication terminal device 200, assigns transmission data to each communication control device (step S38), and performs downlink wireless transmission (step S38). Step S39). The feedback cycle in which the communication control apparatus acquires feedback information from the communication terminal device 200 is the same as the slot length cycle in the shortest interval. The communication control apparatus 100 can perform the slot allocation cycle at the same cycle as the feedback cycle. On the other hand, for simplification and reduction of operating power, the communication control apparatus 100 does not necessarily perform slot allocation in the same cycle as the feedback cycle.

  As described above, in the present embodiment, each communication terminal apparatus measures reception quality (propagation channel status), and adds additional information when notifying the feedback to the communication control apparatus, thereby specifying a transmission format. Format information can be notified. Thereby, the communication control apparatus can select an appropriate transmission format for each communication terminal apparatus. Further, each communication terminal apparatus determines the transmission format of data transmitted from the communication control apparatus, so that the processing of the communication control apparatus can be reduced. Furthermore, as in the first embodiment, the feedback information transmitted from each communication terminal apparatus does not necessarily include all the propagation path conditions, so that the transmission power of the communication terminal apparatus can be reduced. Since information of an appropriate transmission format is fed back from each communication terminal apparatus, the communication control apparatus can perform more efficient data allocation.

  In each of the above embodiments, the wireless communication system has been described on the assumption that the 1-cell repetitive OFDM / (TDMA, FDMA) communication method is used. However, between communication devices that allocate data to a plurality of slots specified by one or more time channels defined by a certain time length and one or more frequency channels defined by a certain frequency band, and transmit the data. The present invention can be applied to any wireless communication system that uses a plurality of transmission formats for assigning data to slots.

It is a block diagram which shows schematic structure of the communication control apparatus which concerns on 1st Embodiment. It is a block diagram which shows schematic structure of the communication terminal device which concerns on 1st Embodiment. It is the figure which showed the example of exchange of the radio | wireless data of the communication control apparatus of 1st Embodiment, and a communication terminal device, and each operation | movement in time series. It is a figure which shows an example of the operation | movement which the communication terminal device of this embodiment produces | generates feedback information. It is a figure which shows an example of the slot structure (when using all frequency bands) of a frequency diversity format. It is a figure which shows an example of the slot structure (when using some frequency bands) of a frequency diversity format. It is a figure which shows an example of a slot structure of a multiuser diversity format. It is the figure which showed the example of exchange of the radio | wireless data of the communication control apparatus of 2nd Embodiment, and a communication terminal device, and each operation | movement in time series. It is a figure which shows an example of the operation | movement which the communication terminal device of 2nd Embodiment produces | generates feedback information. It is a figure which shows an example of a frame structure of OFDM / (TDMA, FDMA) two-dimensional.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Communication control apparatus 101 Transmission format judgment part 102 Data allocation part 103 Data modulation part 104 S / P conversion part 105 IFFT part 106 GI insertion part 107 D / A conversion part 108 Wireless transmission part 109 Antenna part 110 Wireless reception part 111 A / D conversion unit 112 GI removal unit 113 FFT unit 114 P / S conversion unit 115 data demodulation unit 116 control side transmission unit 117 control side reception unit 200 communication terminal device 201 data modulation unit 202 S / P conversion unit 203 IFFT unit 204 GI insertion Unit 205 D / A conversion unit 206 wireless transmission unit 207 antenna unit 208 wireless reception unit 209 A / D conversion unit 210 GI removal unit 211 FFT unit 212 P / S conversion unit 213 data demodulation unit 214 reception quality measurement unit 215 transmission format selection Unit 216 feedback information generation unit 217 Terminal side transmitter 218 Terminal side receiver

Claims (24)

A communication terminal apparatus that communicates with a communication control apparatus using a plurality of slots specified by one or more time channels defined by a certain time length and one or more frequency channels defined by a certain frequency band. There,
A terminal-side receiving unit that receives control information from the communication control device;
A reception quality measurement unit that measures reception quality of a plurality of slots using the received control information;
A transmission format selection unit that selects one transmission format from a plurality of transmission formats that allocate data to the plurality of slots based on the measured reception quality measurement results;
A feedback information generating unit that generates feedback information for notifying the communication control device of reception quality information indicating reception quality in a plurality of slots, and transmission format information specifying a selected transmission format;
A terminal-side transmission unit that transmits the generated feedback information to the communication control device ,
The feedback information generation unit generates reception quality information based on the measured reception quality measurement result, and generates feedback information including the generated reception quality information and the transmission format information. .   The feedback information generation unit sets a plurality of different data formats corresponding to the plurality of transmission formats, selects a data format corresponding to the selected transmission format, and selects the measured reception measurement result as the selected data format. The communication terminal apparatus according to claim 1, wherein the reception quality information is generated by editing, and the generated reception quality information is used as feedback information. Wherein the feedback information generator calculates an average measurement result of reception quality measurement results are average of multiple slots, thus to the calculated average measurement result feedback information, and the reception quality information, the first transmission format The communication terminal apparatus according to claim 2, wherein feedback information for notifying transmission format information for designating is generated.   The feedback information generation unit generates feedback information for notifying the reception quality information and transmission format information designating a second transmission format by using the reception quality measurement result of each of the plurality of slots as feedback information. The communication terminal device according to claim 2. The terminal-side receiving unit receives control information including feedback request information specifying a slot,
The reception quality measuring unit measures the reception quality of the slot specified in the feedback request information;
The communication terminal apparatus according to claim 1, wherein the feedback information generation unit generates reception quality information based on a reception quality measurement result of the designated slot. The reception quality measurement unit selects a predetermined number of slots as a feedback slot from a plurality of slots, measures the reception quality of the selected feedback slot,
The communication terminal apparatus according to claim 1, wherein the feedback information generation unit generates reception quality information based on a reception quality measurement result of the feedback slot. The reception quality measurement unit selects a predetermined number of slots from the measured reception quality measurement results of a plurality of slots as feedback slots,
The transmission format selection unit selects one transmission format from a plurality of transmission formats based on the reception quality measurement result of the selected feedback slot,
The communication terminal apparatus according to claim 1, wherein the feedback information generation unit generates reception quality information based on a reception quality measurement result of the feedback slot. 8. The communication terminal apparatus according to claim 7, wherein the reception quality measurement unit selects a predetermined number of slots as feedback slots in order of good reception quality. The reception quality measuring section selects a predetermined number of slots in a good order of the reception quality, further, by selecting a predetermined number of slots in ascending order of reception quality, according to claim 7, characterized in that the feedback slot Communication terminal device.   2. The reception quality measurement unit uses at least one of propagation path quality calculated from received signal power and carrier signal power, or received data quality calculated from an error amount of received data. The communication terminal device described.   2. The communication according to claim 1, wherein the reception quality measuring unit measures reception quality of the same slot at a plurality of time points, and determines its own moving speed based on the measured reception quality at the plurality of time points. Terminal device.   The plurality of transmission formats include a multi-user diversity system that allocates communication terminal devices having good propagation path conditions for each slot, and a frequency diversity system that uses a plurality of slots in the frequency direction and transmits so as to obtain a diversity effect. The communication terminal device according to claim 1, comprising at least one of the following. Multiple communications using multiple transmission formats that allocate data to multiple slots specified by one or more time channels defined by a certain time length and one or more frequency channels defined by a certain frequency band A communication control device that communicates with a terminal device,
A control-side transmitter that transmits control information to the communication terminal device;
Corresponding to the control information, a control-side receiving unit that receives feedback information that notifies reception quality information indicating reception quality and transmission format information that specifies one transmission format from the plurality of transmission formats;
A transmission format determination unit that selects a transmission format to be applied to the communication terminal device based on the received feedback information;
A data allocating unit that allocates data having the communication terminal device as a transmission destination to each slot based on the selected transmission format and the reception quality information;
The control-side transmission unit uses the selected transmission format to transmit data having each communication terminal device assigned to each slot as a transmission destination ,
The control-side receiving unit receives feedback information including transmission format information specifying any of the plurality of transmission formats,
The communication control apparatus, wherein the transmission format determination unit selects one transmission format from a plurality of transmission formats based on transmission format information included in feedback information . The control-side receiving unit receives, as feedback information, reception quality information edited using any of a plurality of different data formats,
The transmission format determination unit, based on the data format indicated by the reception quality information, the communication control apparatus according to claim 13, wherein selecting one transmission format from a plurality of transmission formats. 15. The transmission format determination unit according to claim 14, wherein the transmission format determination unit selects a first transmission format when the reception quality information is an average measurement result obtained by averaging reception quality measurement results of a plurality of slots. Communication control device. 15. The communication control apparatus according to claim 14, wherein the transmission format determination unit selects a second transmission format when the reception quality information is a reception quality measurement result of each of a plurality of slots. The control-side transmission unit transmits control information including feedback request information specifying a slot position for requesting measurement of reception quality,
The control-side receiving unit receives feedback information that notifies reception quality information and transmission format information at a slot position specified in the feedback request information,
The data allocation unit based on the reception quality information and the selected transmission format in the specified slot position, according to claim 13, the data of which destination is the communication terminal device and allocates to each slot Communication control device. The control-side receiving unit selects a predetermined number of slots as a feedback slot from a plurality of slots, and receives feedback information for notifying reception quality information and the transmission format information in the selected feedback slot,
The data allocation unit, based on said reception quality information in the feedback slots and said selected transmission format, communication of claim 13, wherein the data of which destination is the communication terminal device and allocates to each slot Control device. The plurality of transmission formats include a multi-user diversity system that allocates communication terminal devices having good propagation path conditions for each slot, and a frequency diversity system that uses a plurality of slots in the frequency direction and transmits so as to obtain a diversity effect. The communication control apparatus according to claim 13 , comprising at least one of the following. Between a communication terminal device and a communication control device using a plurality of slots specified by one or more time channels defined by a certain time length and one or more frequency channels defined by a certain frequency band A wireless communication system for performing communication,
The communication terminal device
A terminal-side receiving unit that receives control information from the communication control device;
A reception quality measurement unit that measures reception quality of a plurality of slots using the received control information;
A transmission format selection unit that selects one transmission format from a plurality of transmission formats that allocate data to the plurality of slots based on the measured reception quality measurement results;
A feedback information generating unit that generates feedback information for notifying the communication control device of reception quality information indicating reception quality in a plurality of slots, and transmission format information specifying a selected transmission format;
A terminal-side transmission unit that transmits the generated feedback information to the communication control device,
The communication control device includes:
A control-side transmitter that transmits the control information to the communication terminal device;
In response to the control information, a control-side receiving unit that receives the feedback information from the communication terminal device;
A transmission format determination unit that selects a transmission format to be applied to the communication terminal device based on the received feedback information;
A data allocating unit that allocates data having the communication terminal device as a transmission destination to each slot based on the selected transmission format and the reception quality information;
The control-side transmission unit uses the selected transmission format to transmit data having each communication terminal device assigned to each slot as a transmission destination,
The terminal-side receiving unit receives data of a transmission format specified by the transmission format information from the communication control device ,
The feedback information generation unit generates reception quality information based on the measured reception quality measurement result, generates feedback information including the generated reception quality information and the transmission format information,
The control-side receiving unit receives feedback information including transmission format information specifying any of the plurality of transmission formats,
The wireless communication system, wherein the transmission format determination unit selects one transmission format from a plurality of transmission formats based on transmission format information included in feedback information . A communication terminal apparatus that communicates with a communication control apparatus using a plurality of slots specified by one or more time channels defined by a certain time length and one or more frequency channels defined by a certain frequency band A communication method,
Receiving control information from the communication control device,
Using the received control information, measure the reception quality of multiple slots,
Based on the measured reception quality measurement result, one transmission format is selected from a plurality of transmission formats for assigning data to the plurality of slots,
Generating feedback information for notifying the communication control device of reception quality information indicating reception quality in a plurality of slots and transmission format information specifying the selected transmission format;
Send the generated feedback information to the communication control device,
Receiving data of the transmission format specified by the transmission format information from the communication control device ;
A communication method , wherein reception quality information is generated based on the measured reception quality measurement result, and feedback information including the generated reception quality information and the transmission format information is generated . Multiple communications using multiple transmission formats that allocate data to multiple slots specified by one or more time channels defined by a certain time length and one or more frequency channels defined by a certain frequency band A communication method of a communication control device for communicating with a terminal device,
Send control information to the communication terminal,
Corresponding to the control information, receiving feedback information for notifying reception quality information indicating reception quality and transmission format information designating one transmission format from the plurality of transmission formats,
Based on the received feedback information, select a transmission format to be applied to the communication terminal device,
Based on the selected transmission format and the reception quality information, assigns the data destined for the communication terminal device to each slot,
Using the selected transmission format, send data to each communication terminal device assigned to each slot as a transmission destination ,
Receiving feedback information including transmission format information specifying any of the plurality of transmission formats;
A communication method, wherein one transmission format is selected from a plurality of transmission formats based on transmission format information included in feedback information . Between a communication terminal device and a communication control device using a plurality of slots specified by one or more time channels defined by a certain time length and one or more frequency channels defined by a certain frequency band A communication method of a wireless communication system for performing communication,
The communication terminal device
Receiving control information from the communication control device,
Using the received control information, measure the reception quality of multiple slots,
Based on the measured reception quality measurement result, one transmission format is selected from a plurality of transmission formats for assigning data to the plurality of slots,
Generating feedback information for notifying the communication control device of reception quality information indicating reception quality in a plurality of slots and transmission format information specifying the selected transmission format;
Send the generated feedback information to the communication control device,
Generate reception quality information based on the measured reception quality measurement result, generate feedback information including the generated reception quality information and the transmission format information,
The communication control device includes:
Transmitting the control information to the communication terminal device;
In response to the control information, the feedback information is received from the communication terminal device,
Based on the received feedback information, select a transmission format to be applied to the communication terminal device,
Based on the selected transmission format and the reception quality information, assigns the data destined for the communication terminal device to each slot,
Receiving feedback information including transmission format information specifying any of the plurality of transmission formats;
Based on the transmission format information included in the feedback information, select one transmission format from multiple transmission formats,
The communication control device uses the selected transmission format to transmit data with each communication terminal device assigned to each slot as a transmission destination,
The communication terminal device receives data of a transmission format specified by the transmission format information from the communication control device. The feedback information generating section generates the feedback information measured average result obtained by averaging the reception quality measurement results of the plurality of slots, one of the measured values results a reception quality measurement result of each of the plurality of slots as the reception quality information And
The transmission format determination unit, when the feedback information is the average measurement result, selects a frequency diversity scheme as a transmission format, when the feedback information is the measurement results, the multi-user diversity scheme as a transmission format The wireless communication system according to claim 20 , wherein the wireless communication system is selected.

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